Geranyl pyrophosphate enzymatic cyclization

These results suggest that samples of this sponge differ in their enzymatic capabilities concerning the cyclization of geranyl-geranyl-pyrophosphate. 

With the preceding reviews of the enzymology of monoterpene cyclization and of model studies relevant to the cyclization process, it is possible to formulate a unified stereochemical scheme for the enzymatic cyclization of geranyl pyrophosphate (Figure 4). The proposal which follows is consistent with the implications of parallel advances in related fields, most notably the contributions of Cane (8,16,24,25,52), Arigoni (67) and Coates (68,69) on the stereochemistry of sesquiterpene and diterpene cyclizations, and of Poulter and Rilling (29,70) on the stepwise, ionic mechanism of prenyl transferase, a reaction type of which several monoterpene, sesquiterpene and diterpene cyclizations are, in a sense, the intramolecular equivalents. 

Croteau R (1992) Biosynthesis of thujane monoterpenes. In Hopp R,Mori K (eds) Recent developments in flavor and fragrance chemistry. VCH, Weinheim Germany, p 263 Croteau R (1992) Monoterpene biosynthesis cyclization of geranyl pyrophosphate to (+)-sabinene. In Teranishi R, Takeoka GR, Guntert M (eds) Flavor precursors thermal and enzymatic conversions. American Chemical Society, Washington DC, ACS Symp Series 490, p 8... 

Fig. 3. Stereochemical scheme for the enzymatic cyclization of geranyl pyrophosphate (GPP) to bornyl pyrophosphate (BPP) via linalyl pyrophosphate (LPP).

Saito, and C. Chang, Mechanism of the pyrophosphate migration in the enzymatic cyclization of geranyl and llnalyl pyrophosphates to (+)-and (-)-bornyl pyrophosphates. Biochemistry 24 7077 (1985). 

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